Fleece layers are used to lay multiple layers of a card web, produced by a carding machine, as uniformly as possible on an output apron. The card web is usually guided first through an upper carriage and proceeds from there to a laying carriage, through the laying gap of which the card web is deposited onto the output apron. At least two card web conveyor belts are used to guide the card web through the fleece layer. The movements of the card web conveyor belts, of the upper carriage, and of the laying carriage are controlled so as to coordinate with each other.
Between the infeed area of the fleece layer and the upper carriage, it is advantageous for the card web not only to rest on a card web conveyor belt but also to be enclosed by a cover belt from above. This prevents the fibers from being blown away from the card web and thus ensures the uniformity of the laid fleece. Designs of this type are known from, for example, DE 195 43 623 A1, EP 1 136 600 A1, and EP 1 870 499 B1.
The disadvantage of the fleece layer designs indicated above is the complexity of the system used to guide the endless cover belt. This complexity requires a large number of components and considerable mechanical effort.